Distance Constraints

Distance constraints link pairs of particles together, forcing them to keep a certain distance (we will call this distance the "rest lenght" of the constraint) between them. Obi creates a stretch constraint for each edge of your cloth mesh, or for each segment of your rope. These constraints are vital to the look of your cloth and ropes, so understanding all their parameters is crucial.

Stretching scale

This is a scale factor for the rest lenght of each constraint. The initial rest lenght of any distance constraint is a fixed value set by the ObiActor using it. You can increase this distance (making the constraints expand) by setting a scale factor > 1, or reduce it (making the constraints shrink) by using a scale factor < 1.

stretching scale: 0.75
stretching scale: 1
stretching scale: 1.25

Stiffness

This controls how much constraints can stretch past their rest lenght. At low values, constraints will offer little resistance to exceeding their rest lenght, making the cloth look elastic. High values will make it harder for constraints to stretch.

stretching stiffness: 0.7
stretching stiffness: 1

Slack

This is the percentage of compression allowed by the constraints before kicking in. A value of 0 will cause constraints to resist any compression, with a value of 1 they won't resist compression at all. A value of 0.5 will cause the constraints to resist compression once their length is below 50% of their rest length. Very light cloth (like silk, or a fine net) will benefit of high slack values.